package util;

import com.mysql.jdbc.jdbc2.optional.MysqlDataSource;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

/**
 * 数据库连接的工具类
 * 1、提供connection对象
 * 2、提供关闭资源的方法
 */
public class DBUtil {
    private  DBUtil(){

    }
    private static MysqlDataSource dataSource;
    private static volatile Connection connection;

    private static MysqlDataSource getDataSource(){
        if(dataSource == null){
            synchronized (DBUtil.class){
                if(dataSource == null){
                    dataSource = new MysqlDataSource();
                    dataSource.setURL("jdbc:mysql://127.0.0.1:3306/ordersystem?characterEncoding=utf8&useSSL=true");
                    dataSource.setUser("root");
                    dataSource.setPassword("12345678");
                }
            }
        }
        return  dataSource;
    }

    //得到connection对象
    public static Connection getConnection() throws SQLException {
        MysqlDataSource dataSource = getDataSource();
        return dataSource.getConnection();
    }
    //关闭资源
    public static void close(ResultSet resultSet , PreparedStatement statement , Connection connection) throws SQLException {
        if(resultSet != null){
            resultSet.close();
        }
        if(statement != null){
            statement.close();
        }
        if(connection != null){
            connection.close();
        }
    }
}
